单项选择题 A check valve is another name for （）.

单项选择题 A butterfly valve consists basically of a disc pivoted across the bore of a ring body having the same radial dimensions as the pipe in which it is fitted.According to the above sentence, which of the following statements is not true?（）

单项选择题 Unlike the globe valve, gate valves give full bore flow without change of direction, such a valve is not suitable to partially open operationAccording to the above sentence, which of the following statements is not true?（）